Semantically enhancing SensorML with controlled vocabularies in the marine domain
KOKKINAKI ALEXANDRA, BUCK JUSTIN, DARROCH LOUISE, JIRKA SIMON AND THE MARINE PROFILES FOR OGC SENSOR WEB ENABLEMENT STANDARDS TEAM
Funded by SenseOCEAN (FP7/2007–2013 under grant agreement No. 61414) Bridges (Horizon 2020 under grant agreement No 635359)
Overview
Introduction
SensorML’s flexibility
Vocabularies
Process
Next steps
Conclusion
Introduction
The marine domain has started implementing Open Geospatial Consortium’s (OGC) Sensor Web Enablement (SWE) standards • Aim to:
– make all types of sensors, transducers and sensor data repositories discoverable, accessible and useable via the Web
• Include: – Sensor Model Language (SensorML), – Observations and Measurements (O&M), – Sensor Planning Service (SPS), – Transducer Markup Language (TML), – Sensor Alert Service (SAS), – Sensor Observation Service (SOS) and – Web Notification Service (WNS).
SensorML
• The main objective is to enable interoperability, first at the syntactic level and later at the semantic level (by using ontologies and semantic mediation), so that sensors and processes
• can be better understood by machines, • utilized automatically in complex workflows, • and easily shared between intelligent sensor web
nodes.
Ability of computer systems to exchange data with
unambiguous, shared meaning
Ability of computer systems to process a syntax and exchange
information
Characteristics
• SensorML flexible enough to describe all types of sensors • “Soft typing” characteristic:
– pre-define in schema every possible property – property types defined outside of the SensorML
schema (typically within an online ontology) and then be used within SensorML as a value to the definition attribute.
SensorML
Identification Classification Keywords Capabilities Characteristics History References Documentation
Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors
<sml:classification> <sml:ClassifierList> <!-- Instrument type of Fast Repetition Rate Fluorometer --> <sml:classifier name=“InstrumentType"> <sml:Term definition= "http://www.example.com/definitions.html#InstrumentType"> <sml:label>Instrument Type</sml:label> <sml:value> active fluorometers </sml:value> </sml:Term> </sml:classifier> </sml:ClassifierList> </sml:classification> <sml:classification> <sml:ClassifierList> <!-- Instrument type of Fast Repetition Rate Fluorometer --> <sml:classifier name=“Category"> <sml:Term definition= "http://www.myexample.com/mydefinitions.html#Category"> <sml:label>Category</sml:label> <sml:value> flurometers </sml:value> </sml:Term> </sml:classifier> </sml:ClassifierList> </sml:classification>
Find sensors that are classified as fluorometers
Section: Classification Term: Category, InstrumentType..? Vocabulary: ? Value: “%fluorometer%”
Consequences
Soft typing • Different terms for the same meaning • Variations in the meaning of the same term • Terms not properly defined • Terms not resolvable • Many different ontologies with variations on the names of same terms • Terms not mapped with each other
Reduce interoperability and discoverability via the web.
SensorML ontology
• SensorML creators have created the SensorML ontology to list these terms, through the Marine Metadata Interoperability (MMI) project, which hosts an Ontology Registry and Repository hosting a number of small project specific controlled vocabularies.
• Since different communities require different terminologies, the ontology can fulfill only a subset of the required concepts.
Solution
“In order to achieve interoperability within and between various sensor communities, implementation of SensorML will require the definition of community specific semantics (within online dictionaries or ontologies) that can be utilized within the framework”
[OpenGIS® Sensor Model Language (SensorML) Implementation Specification]
Marine Community
SWE Marine Profiles
52 North Wiki for SWE Marine Profiles
National Environmental Research Council (NERC) Vocabulary Server 2.0
SWE Marine profiles
Group by partners from several projects and initiatives (AODN, BRIDGES, ENVRI+, EUROFLEETS /EUROFLEETS2, FixO3, FRAM, IOOS, Jerico/Jerico-Next, NeXOS, ODIP/ODIP II, RITMARE, SeaDataNet, SenseOcean, X-DOMES) Aim at developing marine profiles of OGC SWE standards • to serve as a common basis for OGC implementations
Controlled Vocabularies and NVS2.0
Controlled vocabularies: • In information science controlled vocabulary is a carefully selected
list of words and phrases, which are used to tag units of information (document or work) so that they may be more easily retrieved by a search.
NERC Vocabulary Server 2.0 (NVS2.0) • provides access to lists of standardized terms • machine and human readable • W3C Simple Knowledge Organisation System (SKOS), RDF/XML • Vocab Search, Vocab editor
<sml:classfication> <sml:ClassifierList> <!-- Name of the manufacturer of the Sensor X --> <sml:classifier name=“InstrumentType"> <sml:Term > <sml:label>Instrument Type</sml:label> <sml:value> </sml:value> </sml:Term> </sml:identifier> <sml:IdentifierList> </sml:identification>
Classify a Fast repetition rate fluorometer in SensorML to aid the rapid discovery of my sensors
definition= "http://vocab.nerc.ac.uk/collection/W06/current/CLSS0002/">
http://vocab.nerc.ac.uk/collection/L05/current/353/
Find sensors that are classified as fluorometers
Section: Classification Term: InstrumentType Vocabulary: NVS2.0 Value: L05::353
Term values
• Observable property: NVS2.0 Vocabulary P01, P07 • Instrument Type: NVS2.0 Vocabulary L05 • Platform Type: NVS2.0 Vocabulary L06 • Sensor Models: NVS2.0 Vocabulary L22 • Roles: NVS2.0 Vocabularies G04, C86 • Feature of Interest: NVS2.0 Vocabulary C19 • Manufacturer: NVS2.0 Vocabularies L35, C75
Term Definitions: Initial Process
Collected terms from the SWE examples
SWE Marine wiki
Identified common
terms under each section containing
title, definition, alt
label
Post on the wiki
Members add/suggest corrections on the wiki
Revised and submit to the
VMG Published on
the web
SensorML
Identification
Application domain
Call Sign
ICES code
Long name
Manufacturer
Model name
Model Number
Serial number
Short name
UUID
Unique ID
Version
WMO platform number
Classification
Instrument Type
Platform Type
Keywords Capabilities
Accuracy
Damping ratio
Detection limit
Frequency
Measurement range
Operating depth
Precision
Resolution
Response time
Selectivity
Sensitivity
Survival depth
Characteristics
Data storage
Height
Housing material
Length
Weight
Width
History
Calibration
Decommissioning
Delivery
Deployment
Failure
LoanEnd
LoanStart
Loss
Maintenance
Recovery
RepairEnd
RepairStart
Upgrade
References
Data scientist
Manufacturer
Operator
Owner
PI
Technical Coordinator
Wiki SWE examples
Member post on the wiki
SSN ontology
SensorML examples
OpenGIS® SensorML Implementation
Specification
NVS collections for SensorML
Each SensorML section constitutes a vocabulary=collection in NVS • Described in SKOS and RDF/XML • Holds a unique URI • URI pattern: http://vocab.nerc.ac.uk/collection/XXX/current/ Each Collection consists of several terms=concepts Each term • Holds a unique URI • Resolves to RDF/XML • URI pattern: http://vocab.nerc.ac.uk/collection/XXX/current/CODE/
URI Tiiii
http://vocab.nerc.ac.uk/collection/W03/current/ SiiiiiML Hiiiiii Eiiii Tiiii
http://vocab.nerc.ac.uk/collection/W04/current/ SiiiiiML Ciiiiiiiii Siiiiii Tiiii
http://vocab.nerc.ac.uk/collection/W05/current/ SiiiiiML Ciiiiiiiiiiiii Siiiiii Tiiii
http://vocab.nerc.ac.uk/collection/W06/current/ SiiiiiML Ciiiiiiiiiiiii Siiiiii Tiiii
http://vocab.nerc.ac.uk/collection/W07/current/ SiiiiiML Iiiiiiiiiiiiii Siiiiii Tiiii
http://vocab.nerc.ac.uk/collection/W08/current/ SiiiiiML Ciiiiii Siiiiii Tiiii
Process
Member posts on the wiki a
suggestion/correction under a section
containing a title and a definition (alt label)
If other members do not disagree or
Agree it is submitted for revision
Revised and posted on the wiki to get final agreement
Submitted to the VMG and published
on the web
Where next..
• External mappings to the SensorML ontology • Internal mappings to NVS2.0 terms • Process a list of terms that have been added on
the wiki
Conclusions
SensorML’s soft typing characteristic • different versions of sensor descriptions • not interoperable • less discoverable Formalization of the required terms Publication in the form of controlled vocabularies • served by NVS2.0 • governed by group • maintained by British Oceanographic Data Centre (BODC)
Acknowledgment
This work is funded by the European projects • SenseOCEAN (FP7/2007–2013 under grant agreement No. 61414) • Bridges (European Union's Horizon 2020 research and innovation
programme under grant agreement No 635359) Supported Ocean Data Interoperability Platform (ODIP) Supported by the National Environmental Research Council (NERC) National Capability (NC) funding for NC-services, facilities and data (NC-SFD).
Useful Links
NVS2.0 SOAP service: http://vocab.nerc.ac.uk/vocab2.wsdl NVS2.0 RESTFul interface http://vocab.nerc.ac.uk/collection/ NVS2.0 SPARQL endpoint http://vocab.nerc.ac.uk/sparql/ NVS2.0 SensorML collections http://vocab.nerc.ac.uk/collection/W03/current/ http://vocab.nerc.ac.uk/collection/W04/current/ http://vocab.nerc.ac.uk/collection/W05/current/ http://vocab.nerc.ac.uk/collection/W06/current/ http://vocab.nerc.ac.uk/collection/W07/current/ http://vocab.nerc.ac.uk/collection/W08/current/